Drug Interactions — MCQs

Pharmacodynamics deals with:-

An SSRI antidepressant, such as fluoxetine, will be prescribed for an adult patient. You should advise him or her that two of the most likely side effects or adverse responses that may eventually occur at therapeutic blood levels are which of the following?

What is the mechanism of metabolism for alcohol, aspirin, and phenytoin at high doses?

All are true for cytochrome P450 enzymes EXCEPT:

A patient on SSRI sertraline was also prescribed amitriptyline and subsequently developed serotonin toxicity. What is the likely treatment for serotonin toxicity?

A 68-year-old with depression and chronic pain is on amitriptyline. What side effect may arise if given oxybutynin for overactive bladder?

A 25-year-old uncooperative patient of schizophrenia was brought in to the casualty. The Casualty Medical Officer gave an injectable drug to the patient. Two hours later patient develops the following posturing. What is the best treatment?

A 34-year-old woman with bipolar I disorder has been maintained on lithium carbonate 900 mg/day for the past 18 months with good mood stabilisation. She presents to the outpatient clinic complaining of a worsening skin condition that began approximately 3 months after starting lithium. Her serum lithium level is 0.8 mEq/L (therapeutic range). She has no prior personal or family history of skin disease. Over the past 6 weeks, she has been using a moderate-potency topical corticosteroid prescribed by her dermatologist with no meaningful improvement; the eruption has continued to spread and now involves the face, scalp, and upper back, causing significant distress and social impairment. A dermatology referral photograph is shown (Image 1). Which of the following is the most appropriate next step in management?

A 35-year-old woman started on haloperidol for acute psychosis develops fever (102°F/38.9°C), severe muscle rigidity, altered mental status, and autonomic instability 3 days after medication initiation. Laboratory studies show creatine kinase of 15,000 U/L and white blood cell count of 16,000/mm³. Apply the most appropriate management approach.

Which antipsychotic has anti-suicidal properties?